Abstract
Uridine, a pyrimidine nucleoside essential for the synthesis of RNA and biomembranes, was radiolabeled with Tc-99m to obtain a potential tumor imaging agent. The maximal radiochemical yield of about 96.5%, as determined by paper chromatography and instant thin-layer chromatography, was reached under the following optimum conditions: 1 mg of uridine, 20 mu g of SnCl2 center dot 2H(2)O as reducing agent, 20 mg of mannitol as a stabilizer, and pH 8. Tc-99m-uridine is stable in vitro at room temperature for up to 6 h post labeling. The biodistrbution study in tumor-bearing mice shows high target-to-nontarget ratio. These results match with the high docking score of the complex on uridine phosphorylase enzyme. Tc-99m-uridine shows promise as a tumor imaging agent.